--- title: "to_microseconds" slug: "dev-database-reference-sql-functions-date-time-to-microseconds" updated: 2026-10-30T18:19:01Z published: 2026-10-30T18:19:01Z canonical: "docs.vastdata.com/dev-database-reference-sql-functions-date-time-to-microseconds" --- > ## Documentation Index > Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt > Use this file to discover all available pages before exploring further. # to_microseconds *Applies to VAST Cluster 5.5.* *[Functions](/develop/docs/dev-database-reference-sql-functions-index) › [Date and time functions](/develop/docs/dev-database-reference-sql-functions-date-time) › Interval constructors.* Returns an interval of `n` microseconds (millionths of a second), the same as `INTERVAL n MICROSECOND`. Add it to a timestamp, or subtract it, to move by that many microseconds. ## Syntax ``` to_microseconds(n) ``` | Argument | Type | Description | | --- | --- | --- | | `n` | `BIGINT`; also `INTEGER`, `SMALLINT`, or a string that holds a whole number | The number of microseconds. It can be negative. | **Returns:** `INTERVAL`. **Same as:** `INTERVAL n MICROSECOND` for a constant `n`. ## Set up the examples The examples connect with the ADBC driver, as in [VAST Query Engine (ADBC)](/develop/docs/dev-database-integrations-adbc), and work in a schema called `docs_sql_fn_date_time_to_microseconds`. Set `QE_ENDPOINT`, `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY` and `VASTDB_BUCKET` ([SQL reference](/develop/docs/dev-database-reference-sql-index#example-connect-and-use-a-transaction)), and run the blocks in order in one Python session. Below each block is the output you should see. This block connects, defines the `run()` and `plan()` helpers, and creates a table of four readings. Each has a time `ts` and an offset `us` in microseconds (a `BIGINT`). Row 4 has no values: ``` import os import re import adbc_driver_manager import adbc_driver_manager.dbapi as dbapi import adbc_driver_vastdb BUCKET = os.environ["VASTDB_BUCKET"] SCHEMA = f'"{BUCKET}/docs_sql_fn_date_time_to_microseconds"' conn = dbapi.connect( driver=adbc_driver_vastdb.get_driver_path(), db_kwargs={ "vast.db.endpoint": os.environ["QE_ENDPOINT"], "vast.db.access_key": os.environ["AWS_ACCESS_KEY_ID"], "vast.db.secret_key": os.environ["AWS_SECRET_ACCESS_KEY"], }, autocommit=True, ) def server_message(e): """The server's message in a driver error, without the request ID or the echoed statement.""" text = re.sub(r"\[req=0x[0-9a-f]+\]: ", "", str(e)) found = (re.search(r'message: "(.*?)", request_id', text, re.S) or re.search(r"description: (.*)\)", text, re.S)) message = found.group(1) if found else text.strip().splitlines()[-1] message = re.sub(r"^Plan query: '.*?' failed with: ", "", message, flags=re.S) message = re.split(r"\\n|\n", message)[0].replace('\\"', '"') return message.replace(BUCKET, "") def run(sql): """Run one statement. Print the rows it returns, or the error.""" try: with conn.cursor() as cur: cur.execute(sql) rows = cur.fetchall() if cur.description else [] except (adbc_driver_manager.Error, OSError) as e: print(f"{type(e).__name__}: {server_message(e)}") else: print(rows) def plan(sql): """Print the plan without its ~N Rows lines: the table's row count, which can still be 0 just after an insert.""" with conn.cursor() as cur: cur.execute("EXPLAIN " + sql) steps = cur.fetchall()[0][1] print("\n".join(line for line in steps.splitlines() if "Rows" not in line)) TABLE = f"{SCHEMA}.readings" run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}") run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, ts TIMESTAMP, us BIGINT)") run(f"INSERT INTO {TABLE} VALUES " "(1, TIMESTAMP '2024-02-29 00:00:00', 1), " "(2, TIMESTAMP '2026-03-01 08:30:45.123456', 1500000), " "(3, TIMESTAMP '2026-03-01 08:30:45', -250), " "(4, NULL, NULL)") ``` ``` [] [] [(4,)] ``` ## What it does `to_microseconds(n)` returns an interval with no months or days and a time part of `n` microseconds. The ADBC driver shows an interval as a `MonthDayNano` value, in nanoseconds: `to_microseconds(2)` is `MonthDayNano(months=0, days=0, nanoseconds=2000)`. A microsecond is the smallest step of a `TIMESTAMP`: `TIMESTAMP '2024-02-29 00:00:00' + to_microseconds(1)` is `2024-02-29 00:00:00.000001`. A `DATE` plus the interval is a `TIMESTAMP`: `DATE '2026-01-31' + to_microseconds(1)` is `2026-01-31 00:00:00.000001`. The time part isn't turned into days: `to_microseconds(1000000)` is one second, and `normalized_interval(to_microseconds(100))` is still 100 microseconds. ## NULLs and edge cases | Input | Result | | --- | --- | | `NULL`, or a NULL value (row 4) | `NULL` | | `0` | An empty interval: `nanoseconds=0` | | `-1` | `nanoseconds=-1000`, one microsecond back | | `'2'` (a string) | `nanoseconds=2000`: the same as `to_microseconds(2)` | | `CAST(2 AS SMALLINT)` | `nanoseconds=2000`: the same as `to_microseconds(2)` | | `9223372036854775807`, the largest `BIGINT` | Accepted, but the result is wrong: `nanoseconds=-1000` | | `9223372036854775808`, past the largest `BIGINT` | Error: `No function matches the given name and argument types 'to_microseconds(INTEGER_LITERAL)'` | | A fraction, such as `1.5` (a `DOUBLE` fails the same way, naming `DOUBLE`) | Error: `No function matches the given name and argument types 'to_microseconds(DECIMAL(2,1))'` | | A `DATE`, an `INTERVAL` or a boolean | Error: `No function matches the given name and argument types`, for example `'to_microseconds(DATE)'` | The same cases, as the cluster returns them. They use the table and helpers from [Set up the examples](/develop/docs/dev-database-reference-sql-functions-date-time-to-microseconds#set-up-the-examples): ``` run(f"SELECT id, to_microseconds(us) FROM {TABLE} WHERE id = 4") run("SELECT to_microseconds(NULL), to_microseconds(0), to_microseconds(-1), to_microseconds('2'), " "to_microseconds(CAST(2 AS SMALLINT))") run("SELECT to_microseconds(9223372036854775807)") run("SELECT to_microseconds(9223372036854775808)") run("SELECT to_microseconds(1.5)") run("SELECT to_microseconds(DATE '2026-01-01')") ``` ``` [(4, None)] [(None, MonthDayNano(months=0, days=0, nanoseconds=0), MonthDayNano(months=0, days=0, nanoseconds=-1000), MonthDayNano(months=0, days=0, nanoseconds=2000), MonthDayNano(months=0, days=0, nanoseconds=2000))] [(MonthDayNano(months=0, days=0, nanoseconds=-1000),)] InternalError: Binder Error: No function matches the given name and argument types 'to_microseconds(INTEGER_LITERAL)'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'to_microseconds(DECIMAL(2,1))'. You might need to add explicit type casts. InternalError: Binder Error: No function matches the given name and argument types 'to_microseconds(DATE)'. You might need to add explicit type casts. ``` ## Examples The interval for each reading's offset, and the time moved by it: ``` run(f"SELECT id, us, to_microseconds(us), ts + to_microseconds(us) FROM {TABLE} ORDER BY id LIMIT 10") ``` ``` [(1, 1, MonthDayNano(months=0, days=0, nanoseconds=1000), datetime.datetime(2024, 2, 29, 0, 0, 0, 1)), (2, 1500000, MonthDayNano(months=0, days=0, nanoseconds=1500000000), datetime.datetime(2026, 3, 1, 8, 30, 46, 623456)), (3, -250, MonthDayNano(months=0, days=0, nanoseconds=-250000), datetime.datetime(2026, 3, 1, 8, 30, 44, 999750)), (4, None, None, None)] ``` One microsecond after a timestamp and after a date, and one microsecond before a timestamp: ``` run("SELECT TIMESTAMP '2024-02-29 00:00:00' + to_microseconds(1), DATE '2026-01-31' + to_microseconds(1), " "TIMESTAMP '2024-02-29 00:00:00' - to_microseconds(1)") ``` ``` [(datetime.datetime(2024, 2, 29, 0, 0, 0, 1), datetime.datetime(2026, 1, 31, 0, 0, 0, 1), datetime.datetime(2024, 2, 28, 23, 59, 59, 999999))] ``` ## How it runs in VAST The Query Engine runs on the cluster's CNodes, and a query on a table starts with a scan in VAST DataBase (`VAST_SCAN`). VAST DataBase can evaluate a comparison of a column with a constant, but not a function of a column, so an interval built from a column is always computed by the Query Engine: - **In the `SELECT` list,** the scan reads the column and the Query Engine computes `to_microseconds()` for each row it returns. - **In `WHERE`,** the scan sends the columns for every row, and a `FILTER` step in the Query Engine computes the condition and keeps the rows that match. No rows are skipped in storage. The plan of a condition on `ts + to_microseconds(us)` shows the `FILTER` step above the scan: ``` plan(f"SELECT id FROM {TABLE} WHERE ts + to_microseconds(us) > TIMESTAMP '2026-03-01 08:30:45'") ``` ``` ┌───────────────────────────┐ │ PROJECTION │ │ ──────────────────── │ │ #2 │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ FILTER │ │ ──────────────────── │ │ ((ts + to_microseconds(us)│ │ ) > '2026-03-01 08:30:45':│ │ :TIMESTAMP) │ │ │ └─────────────┬─────────────┘ ┌─────────────┴─────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ │ │ Projections: │ │ ts │ │ us │ │ id │ │ │ └───────────────────────────┘ ``` ## Make it faster - **Put the interval on the constant side.** `ts > TIMESTAMP '2026-03-01 08:30:45' + to_microseconds(1)` compares the raw column with a value the Query Engine computes once, so the comparison is pushed down to VAST DataBase and rows that don't match never leave storage. The plan has no `FILTER` step: ``` plan(f"SELECT id FROM {TABLE} WHERE ts > TIMESTAMP '2026-03-01 08:30:45' + to_microseconds(1)") ``` ``` ┌───────────────────────────┐ │ VAST_SCAN │ │ ──────────────────── │ │ Function: VAST_SCAN │ │ Projections: id │ │ │ └───────────────────────────┘ ``` - **Store the result if you filter on it often.** When the offset comes from a column, as `us` does here, there's no single constant to compare with. Compute `ts + to_microseconds(us)` when you write the rows and keep it in its own `TIMESTAMP` column; a comparison of that column with a constant is pushed down. ## Limitations and errors - **Whole numbers only.** A fraction fails with `No function matches the given name and argument types 'to_microseconds(DECIMAL(2,1))'`. For fractions of a larger unit, use [to_milliseconds](/develop/docs/dev-database-reference-sql-functions-date-time-to-milliseconds) or [to_seconds](/develop/docs/dev-database-reference-sql-functions-date-time-to-seconds), which take a `DOUBLE`. - **Very large values come back wrong.** At the top of the `BIGINT` range the result isn't checked: `to_microseconds(9223372036854775807)` returns `nanoseconds=-1000`, a negative interval, without an error. Express long spans in days, months or years. - **No time-zone support.** Adding an interval to a `TIMESTAMP WITH TIME ZONE`, such as `now()`, fails. Cast the value to `TIMESTAMP` first; see [time zones](/develop/docs/dev-database-reference-sql-functions-date-time-time-zones). ## Similar functions | Function or form | What it builds | Result | | --- | --- | --- | | `INTERVAL 1 MICROSECOND` | The same interval, written as a literal | `to_microseconds(1) = INTERVAL 1 MICROSECOND` is `true` | | [to_milliseconds](/develop/docs/dev-database-reference-sql-functions-date-time-to-milliseconds) | Thousandths of a second, from a `DOUBLE` | `to_milliseconds(1) = to_microseconds(1000)` | | [to_seconds](/develop/docs/dev-database-reference-sql-functions-date-time-to-seconds) | Seconds, from a `DOUBLE` | `to_seconds(1) = to_microseconds(1000000)` | | [epoch_us](/develop/docs/dev-database-reference-sql-functions-date-time-epoch-us) | The reverse: the microseconds in an interval, as a `BIGINT` | `epoch_us(to_microseconds(1))` is `1` | | [epoch](/develop/docs/dev-database-reference-sql-functions-date-time-epoch) | The seconds in an interval, as a `DOUBLE` | `epoch(to_microseconds(1))` is `1e-06` | ``` run("SELECT to_microseconds(1) = INTERVAL 1 MICROSECOND, to_milliseconds(1) = to_microseconds(1000), " "to_seconds(1) = to_microseconds(1000000)") run("SELECT epoch_us(to_microseconds(1)), epoch(to_microseconds(1)), normalized_interval(to_microseconds(100))") ``` ``` [(True, True, True)] [(1, 1e-06, MonthDayNano(months=0, days=0, nanoseconds=100000))] ``` Clean up: ``` run(f"DROP TABLE IF EXISTS {TABLE}") run(f"DROP SCHEMA IF EXISTS {SCHEMA}") conn.close() ``` ``` [] [] ``` ## See also - [Date and time functions](/develop/docs/dev-database-reference-sql-functions-date-time): all the date and time functions, and the [interval constructors](/develop/docs/dev-database-reference-sql-functions-date-time#interval-constructors). - [plus](/develop/docs/dev-database-reference-sql-functions-date-time-plus): adding an interval to a date or timestamp. - [Where filters run](/develop/docs/dev-database-reference-sql-select#where-filters-run) and [pushdowns](/develop/docs/dev-database-reference-pushdowns). - [EXPLAIN](/develop/docs/dev-database-reference-sql-explain): how to read a plan.